In Spinneys the other day, I was followed in line at the check-out by a woman with her two delightful, identical, twin daughters. I was cooing at their chubby cheeks and matching get-up when one of them reached out towards the chocolates, which are (unfairly) displayed at their eye-level. The mother shot out a quick, “Don’t touch that! Or the policeman will come and cut you!” The girls looked suitably scared as their eyes swivelled in their heads, checking the horizon for knife-brandishing policemen.

It struck me as being quite a scary tactic, but it seemed to work – and work instantly. It reminded me of a friend who used to threaten her daughter that the big, nasty wolves would come if she didn’t eat her dinner/brush her teeth/generally behave. According to my friend, the threat of scary wolves is quite a normal parenting tool in Belarus where she is from. While lacerating coppers and savage predators aren’t ones I’ve come across before, I certainly remember some fear-mongering going on when I was a child. If you make a face, the wind will change and you’ll be stuck like that forever.

If you stay awake on Christmas Eve, Santa won’t bring you presents. At my grandparents’ apartment, if you made too much noise, the man from upstairs would come and get you. Similarly, at my aunty’s (same side of the family), if you made too much noise the old lady downstairs would come up with her stick.

I asked a few friends if they had been scared into good behaviour as a child, and the stories spilt forth. A monster lives under your bed and, if you get up in the night, he will grab your ankles and pull you under. (Twenty years later, that little girl still won’t buy a bed with space underneath.) If you tell a lie, a witch will turn your mouth into stone. Monsters come around at night and take all the children who are still awake.

You’ll get square eyes if you watch too much TV. If you pick your nose, your head will cave in. There’s a wasp that stings you if you don’t study. We can laugh about them now – well, most of us can – but, when you’re dealing with such impressionable minds, does this sort of fear-inducing threat cause any real damage?

To find out, I turned to The Science of Parenting: How today’s brain research can help you raise happy, emotionally balanced children by Margot Sunderland, the director of education and training at the Centre for Child Mental Health in London. For scientific answers to emotional questions, this book never fails.

According to Margot, fear is one of the primary emotional reactions we have from birth in order to increase our chances of survival (along with rage and separation distress). However, over-stimulation of these reactions can cause stress in a child, which – if prolonged without being calmed – can cause all sorts of long-term issues, including depression and anxiety.

It can also determine how the body and brain react to triggers, causing people to be more prone to stress, fear and anger in later life. Margot calls this ‘fear kindling’, meaning that fear becomes so easy to ignite, it becomes part of a child’s personality. It all sounds pretty serious, but I’m not sure the odd ‘brush your teeth, or they’ll fall out’ line is going to cause long-term depression.

Surely these effects are only a risk in extreme cases of daily fear-kindling? Also, I remember being scared by the Santa threat, but as soon as I realised that Santa was a hoax, that fear disappeared. There hasn’t been any long-term damage (I don’t think). I guess the problem with empty threats is that they are empty.

They may work for a while, but one day your child might call your bluff. And then what? How will you ever get your child to comply once they know that there isn’t really a monster/ogre/wolf/witch, or that your head doesn’t really ever cave in? Surely you’re just setting yourself up for a big fall? And if your child falls for it, and never thinks to question the point, aren’t you going to have to deal with a long list of irrational fears as they grow older?

So what do you do instead? I asked a lovely older Indian woman working in a nail salon, who has a calm aura about her and looks like she has seen a few generations. She says, “There’s no need to use fear. You just explain the real consequences to your child, so she can learn about the world.”

Of course. It makes perfect sense. Brush your teeth to keep them healthy. Go to sleep otherwise you’ll be tired. Don’t pick your nose because you might hurt it. So simple. The next day, as I was leaving the house, I asked my daughter to tidy her room. She declined in a humorous-verging-on-cheeky way. I insisted, without threat – tidy your room, or it will be messy when you come home. “That’s OK,” she says. “I like it messy.” Stumped. Where’s a scary witch when you need one?

Aquarius is tweeting: Follow Louisa Wilkins on @louisa_aquarius